The following tip is provided courtesy of Wayne Maples. Visit his site at NT tip site. As Wayne mentions in his introduction to the tip, it does fall slightly into the hacking realm, but, since this particular tip requires physical access
This tip is certainly in the hacking or hacker realm, but the information is readily available on the Internet. I will lay out a technique to recover the Administrator's password in NT and methods to impede the inappropriate use of these tools by hacker types. There are other ways to do this, but the one here is the easiest.
There are Linux boot disks that have NT file system drivers and software that will read the registry and rewrite the password hashes for any account including the Administrators. It is as simple as:
- Shutdown or turnoff the PC.
- Put the book disk in the PC and reboot.
- Respond to the Linux prompts.
- Select the account whose password hash needs to be rewritten & enter a new password.
- Reboot and access using the new password.
I have seen the Linux boot disks fail primarily on SCSI-based boxes when the boot disk did not have the proper SCSI driver or when there was some problem detected in the SCSI setup. I have also seen PCs on which the Linux boot disk works but the SAM seems to be invisible to Linux (although its in its standard location, and later access with NTFSDOS allows it to be copied).
Since this method will allow anyone to change the administrator password for an NT system, physical security of systems becomes paramount. Some methods to improve physical security include:
- Lock the PC up.
- Enable power-on passwords.
- Lock PC cases.
- Set the BIOS to boot from the hard disk, not from floppy.
- Remove the floppy and lock the case.
- Apply Microsoft's syskey to encrypt the hashes.
Note: Use this information at your own risk. Any attempt to circumvent an operating system's normal security can be disastrous. If you are really, really stuck - this tip may be for you.
To read this tip in it's entirety click here.
This was first published in May 2000